Waste red-mud is the residual product of the aluminum industry. It is obtained from Bauxite after the extraction of aluminum oxide with alkali solution. Since the residue still contains about 10% alkali, the disposal of red-mud may pollute the environment. A typical sample of the red-mud has shown the following analysis:
______________________________________ SiO.sub.2 14.6% TiO.sub.2 7.2% Al.sub.2 O.sub.3 22.6% Fe.sub.2 O.sub.3 35.6% Na.sub.2 O 9.1% Others 10.9% ______________________________________
The composition will vary depending upon the purity of the ore, type and concentration of alkali, type of extraction process, efficiency of extraction, etc. The foregoing analysis is for demonstration purposes only and is not meant to limit the composition of the red-mud.
The disposal of waste PVC has proven to be an environmental problem. Burning the material produces smoke and hazardous gases such as HCl. The present invention reduces these problems. The processes of the present invention utilize the convenience of the Banbury mixer, but other processing equipment can be used such as internal mixers, roll mills, extruders or other processing equipment familiar to those skilled in the art.